Value does not return if #codename using javascript ajax

If I press the Tab key, I want to display the value of the next cell using javascript and ajax.

This is my HTML code:

<input type="text" name="ccode" id="target" class="td-size" autocomplete="off" onchange="get(this.value);">
<input type="text" name="cname[]" class="td-size code_name" id="codename">

javascript code

<script type="text/javascript">
        function get(val){
            $.ajax({
                url: "ajaxData.php",
                type: "POST",
                data: 'ccode='+val,
                success:function(data){
                    $('#codename').html(data);
                    alert(data);
                    
                }
            });
        }
    </script>